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AUTONOMIC DAMAGE AND BLOOD PRESSURE REGULATION IN SPINAL CORD INJURED PATIENTS COMPARED TO ABLE BODIED SUBJECTS
Author(s) -
Evans Joyce,
Aslan Sevda,
Randall David,
McDowell Susan,
Hartman Andrea,
Taylor Robert,
Ziegler Michael,
Knapp Charles
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1429-d
Subject(s) - medicine , blood pressure , heart rate , baroreflex , blood volume , plasma renin activity , anesthesia , spinal cord injury , perfusion , cardiology , venous return curve , spinal cord , hemodynamics , endocrinology , renin–angiotensin system , psychiatry
Our goal was to quantify blood pressure regulation in able‐bodied (AB) and spinal cord injured (SCI) subjects during head up tilt (HUT). METHODS We measured fluid shifts, hormonal changes, blood pressure (AP, FinaPres), calf circumference (CC, Hokanson), perfusion of upper and lower body skin (Perimed), heart rate (HR) and impedance measures (BoMed) of cardiac function in 11 able‐bodied (AB), 5 paraplegic (PARA) and 5 tetraplegic (TETRA) subjects. Differences were tested with two factor (groups and tilt level) ANOVA and accepted at p ≤ 0.05. RESULTS In response to tilt, AB and PARA regulated blood pressure more effectively than TETRA, and SCI subjects shifted plasma out of the vasculature more rapidly than AB subjects. Plasma catecholamines and renin activity were higher for SCI subjects. Perfusion of the forearm was not different between groups, but SCI had lower shin perfusion than AB. Both PARA, and to a greater extent, TETRA, demonstrated a loss of correlation between blood pressure and heart rate. CONCLUSIONS The loss of blood pressure regulation following spinal cord injury had multiple sources: 1) loss of fluid regulation (greater venous pooling, loss of plasma volume and lower shin perfusion) 2) increased hormonal lability (reduced inhibition of catecholamines and renin) and 3) reduced baroreflex mediation of heart rate due, in part, to reduced oscillations in blood pressure. Supported by KySCHIRT, R022602, R00827, NASA EPSCoR WKU52611 and Cardinal Hill Hospital